If its this gun there is no NFA paperwork as it is a pistol and all pistol rules would apply budsgunshop.com/product_info.php/products_id/108772/sig+sauer+mcx+cylinder+bore+rattler+300+black+black%2fcoy

Rob, The MCX Rattler Canebrake is the newest addition to the MCX family. Created for those that desire the MCX as a suppressed system, and eliminates the need to purchase additional components to do so. The Rattler Canebrake comes with a factory installed inert training device, making it operable right out of the box while NFA paperwork and waiting periods are completed, and then is easily convertible to run suppressed. ------------ The MCX Rattler Canebrake comes as a suppressor ready platform with an SD handguard and inert training device that mimics the size and weight of the SIGSRD762 suppressor and assure all muzzle flash is past the shooters hand when reaching out on the handguard during operation without a functional suppressor installed. With the MCX Rattler Canebrake there’s no need for the purchase of a shorter barrel kit and SD Handguard to have a suppressed MCX system, simply unthread the inert training device, install your suppressor, and select the appropriate gas setting for your ammunition.